Inheritance analysis of sugar and organic acid components in blueberry hybrid progenies

Blueberry is a small berry species of high economic value that has experienced rapid development in recent years. The composition and content of sugar and acid are critical determinants of fruit flavor. To investigate the genetic principles of sugar and acid components in blueberry fruits, three varieties with distinct flavor profiles were pairwise crossed, and the content of sugar and acid components in all progeny and parents was determined. The results showed that the glucose content was higher than that of fructose, and the combined proportion of these two sugars exceeding 95 %. Citric acid and quinic acid were identified as the major acids, and the parents and offspring could be categorized into two primary groups: a citric acid-dominant group and a quinic acid-dominant group. The variation coefficient of the main acids (38.95 % and 65.33 %) was higher than that of the main sugars (14.37 % and 16.55 %). The high H² values for glucose and fructose (0.80 and 0.83) suggested their genetic inheritance was relatively stable. Glucose and fructose exhibited similar inheritance patterns. The negative average R_Hm values and the relatively high LL values—63.5 % for glucose and 39.8 % for fructose—suggested a declining trend of these traits. Moreover, when a high-glucose or high-fructose variety was used as the maternal parent, the average glucose or fructose content in the offspring was higher than that observed in reciprocal crosses, indicating that the selection of maternal parent during the breeding process has important effects on these traits. Quinic acid also exhibited maternal inheritance, whereas citric acid and malic acid did not display this pattern of inheritance. In all combinations, the Ta value exceeded 1, and HM % ranged from 57 % to 81 %, indicating citric acid exhibited transgressive inheritance. The mixed major gene and polygene inheritance model analysis was performed. It was found that, the majority of the combined genetic models for glucose, fructose, and citric acid were found to be 2MG-AD, governed by two pairs of additive and dominant genes. Notably, the additive effect was more significant than the dominant effect, while the heritability of major genes exhibited substantial variation across different parental combinations. This study will establish a foundation for parental selection in hybridization and accelerate the process of blueberry breeding.